This invention relates to a water-based, fast-acting pest bait containing a water-sensitive insecticide as the active ingredient for controlling insects, particularly cockroaches.
Historically, toxic baits for controlling crawling insects such as cockroaches have been water-based. With cockroaches especially, water is presumed necessary for good bait performance. Unfortunately, water-based bait products rapidly lose effectiveness due to water loss, rancidity, break-down of active ingredients and other factors. Studies of water-based paste baits have confirmed that water loss, repellent properties of active ingredients, and insecticide resistance are the most important factors affecting bait performance. Appel, A. G., J. Econ Entomol. 85 (4):1176-1183 (1992), Robinson, W. H., Proceedings of the National Conference on Urban Entomology 77-91 (1992), and Rust, N. K., xe2x80x9cManaging Household Pestsxe2x80x9d, in Advances in Urban Pest Management, G. W. Bennett and M. Owens (eds), Van Norstrand Reinhold, N.Y. 335-368 (1986).
One approach to improve on water-based insecticide products has been to use a dust or a paste composition which includes a so-called water powder with the insecticide. This water powder is water encapsulated with hydrogenated soybean oil. Such a product is described in U.S. Pat. No. 5,820,855. Unfortunately, dust compositions have disadvantages such as drifting of the material when applied.
Water-free fat-based pest bait products are described in U.S. Pat. Nos. 5,464,613 and 5,464,613. These compositions are paste forms and include as a major ingredient a fat-based carrier. Although paste products do not drift, they are difficult to apply and require an applicator in applying pastes in cracks and crevices or into voids. Another disadvantage of the paste, water-free products are that they are not as fast-acting as water-based products, especially against cockroaches.
Acephate is a very desirable insecticide, particularly in killing cockroaches. Acephate""s desirability is based on the fact that there is no known insecticide resistance and because it has a very low mammalian toxicity. However, acephate is not stable in water-based matrices over time. Although acephate has been described in the above water-free, fat-based patents, it is not currently used as an active ingredient in any commercially available cockroach bait. There is thus a need for improved rapid acting, water-based baits that utilize water-sensitive insecticides.
We have found in the present invention a method which allows a water-sensitive insecticide, for example, acephate, to be used successfully in a water-based matrix. The invention is a composition which, if desired, can be prepared at the site of application and applied to cracks, crevices and voids. The composition is active when formulated and, when applied, results in rapid kill of insect pests, particularly cockroaches. A preferred rapid acting composition is in the form of a gel.
Accordingly, the invention in its first aspect is a process for preparing a ready-to-use insecticidal bait composition including the steps of (a) dissolving a water sensitive insecticide in a specified amount of water, (b) combining the resulting insecticidal solution with a bait base containing a mixture of feeding stimulants and optionally containing one or more gelling agent(s), (c) agitating the resulting combination until thoroughly mixed, and, if desired, (d) allowing the mixed combination to form a gel or paste.
The present invention in a second aspect provides a ready-to-use insecticidal bait composition having a viscosity between about 50,000 to about 1,500,000 centipoise including (a) about 0.1 to 5.0 wt-% of a water-sensitive insecticide, (b) about 3 to 40 wt-% water, and (c) the balance being a bait base.
A third aspect of the present invention is a method of controlling insect pests, particularly cockroaches, by applying to areas to be controlled an effective amount of the above composition.
Finally, a fourth aspect of the present invention is a kit which can be used by the ultimate consumer at the site of application which contains the means for the preparation and application of the above-described composition, optionally in gel form, and includes (a) a closed impermeable container having a water-sensitive insecticide pellet or powder therein, and (b) a closed packet including a base bait including feeding stimulants and, optionally, one or more gelling agent(s). The kit may further include a means for dispensing the ready-to-use bait. Otherwise, the mixing packet may be used to apply the composition.